The present invention generally relates to a skull pin assembly used with surgical head frames and, in particular, relates to a seamless tip and housing skull pin assembly used in surgical head fixation devices, such as skull clamps, which allows for effective imaging of a patient's skull while undergoing imaging procedures, such as computed tomography (CT) and magnetic resonance imaging (MRI).
Skull pins typically are used in surgical head fixation devices for rigidly supporting the head of a patient during neurosurgical and cervical spine procedures. A typical head fixation device is illustrated in FIG. 1. The head fixation device 100 works like a clamp, or vise, to keep the head of the patient steady as surgeries are performed. Typically, on one side of the head fixation device is a rocker arm 110 containing two skull pins 115 and on the opposing side is a mechanism 120 to engage and advance a third pin 125 into the skull of the patient. When the skin on the skull of the patient is engaged with the skull pins, it is important that the skull pin pierces the skin and does not disrupt its movement as the skull pin further engages the skull bone. Certain skull pin designs for children have been known to cause necrosis where the area just behind the tip of the skull pin compresses the skin of the skull. Therefore, it is desirable to have the tip and housing surfaces of the skull pin assembly create a continuous transition where the tip and housing meet.
After the skull pins are positioned onto the patient's skull, a potential problem may occur when a diagnostic scan of the head is needed after the placement of the head fixation device. The problem may occur when the skull pins are in the area needing scanned. Since the head fixation device and skull pins are optimally located on the head for fixation and support, the skull pins may be in a less desirable location with regard to the imaging plane. Additionally, the skull pins are typically comprised of a metal or some other conductive material that may cause artifact to appear on the images. An artifact is any visible feature or distortion in an output image that is not present in the object being scanned. Artifacts generally degrade an image, and, if severe enough, can impair interpretation of the image. The problem of skull pins causing artifact is becoming more common due to surgical imaging procedures being performed intra-operatively (i.e., a magnetic resonance (MR) or a computed tomography (CT) scanning machine is employed in the operating room). Surgeons frequently want to treat the patient by using such an imagining machine to scan the head of a patient during the surgical procedure; however, the metallic, or conductive, skull pins in the head fixation device stabilizing the patient's head may cause artifact on the scanned images.
Therefore, there is a need for skull pins that rigidly supports the head of a patient in a head fixation device during neurosurgical and related procedures which allows for effective imaging of the head of the patient with the skull pin in place.
There is yet another need for a skull pin assembly comprised of two components, a tip and a housing, where the meeting surfaces of the two components creates a continuous and seamless transition from tip to housing where the components meet, in order to prevent the disruption of the movement of the skin on the head as the pin pierces the skin and further engages the skull bone.
There is still another need for a cost effective skull pin assembly where the skull pin assembly provides limited artifact in a variety of different imaging situations while providing easy of use.